imagine driving a hitbox. Also it begs the question why is the karts collision so sharp? Why isn't it just a rectangular prism? Do all speedkarts use that collision box?
having sharp corners on vehicle collision boxes (or any in general tbh) makes them a lot more prone to getting stuck in bricks/the ground/other vehicles as the corners are more likely to intersect other collisions
it also can result in cases where you cant flip over upside down vehicles, but that may be a plus for some people.